<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>案例2</title>
		<style type="text/css">
			span{
				color: red;
			}
		</style>
	</head>
	<body>
		<span>用户按下键盘，显示keyCode</span>
	</body>
</html>
<script src="../js/jquery-3.5.1.min.js" type="text/javascript" charset="utf-8"></script>
<script src="./js/test2.js" type="text/javascript" charset="utf-8"></script>